This research program addresses itself to the problem of the structure and function of vascular wall and cardiac cells to injury. The problems of behavior of the cells of the artery wall and differences in the properties of the cells of human atherosclerotic plaques are being studied. The fact that atherosclerotic plaque cells in the human disease are clonal and its new implications for the causes and development of atherosclerosis are being explored in relation to operations of known risk factors. The role of hypertension in modifying endothelial cell turnover is under investigation. How endothelial cells produce basal lamina and the mechanisms of platelet interaction with basal lamina are being investigated. The genesis of catecholamine-induced cardiomyopathy is being studied. How mast cells secrete biogenic amines, heparin and associated enzymes is being studied. BIBLIOGRAPHIC REFERENCES: Moss, Ned S. and Benditt, Earl P. Human Atherosclerotic Plaque Cells and Leiomyoma Cells. Comparison of in vitro gRowth characteristics. Am. J. Path. 78:175-186, 1975. Schwartz, S. M., Stemerman, M. and Benditt, E.P. The aortic intima. II. Repair of the aortic lining after mechanical denudation. Amer. J. Path. 81:15-52, 1975.